You copied video off a camcorder — a Sony, Panasonic, or Canon — or pulled it from an AVCHD disc, and you've got files ending in .mts or .m2ts. Drag one into your browser and nothing happens; double-click and your media player may not know what to do either.

These are AVCHD files, and they're a specific kind of stubborn. Here's why browsers won't open them, and how to play them in a browser tab anyway — decoded locally, with no conversion and no upload.

What M2TS / MTS Files Are

.mts and .m2ts are the container format AVCHD uses — the format consumer HD camcorders record in, and a close relative of the streams on Blu-ray discs. The two extensions are essentially the same thing:

• .mts is what you see on the camcorder / SD card.
• .m2ts is the same data after importing to a computer or disc.

Under the hood it's a BDAV MPEG transport stream — a cousin of the .ts files used in broadcasting (see playing .TS files). The video inside is almost always H.264 (AVCHD), with Dolby Digital (AC-3) audio.

Here's the catch, and it's the familiar one: the video codec (H.264) is something browsers can decode — but the transport-stream container is not something the <video> tag opens as a file. So a perfectly decodable video sits locked inside a wrapper the browser won't read. (Our video formats guide covers this container-vs-codec split in full.)

The Usual Fixes — and Why They Drag

1. Convert it (the camera's software, or HandBrake)

Camcorder bundles and tools like HandBrake will transcode AVCHD to MP4. It works, but it's slow, makes a second copy, and is a chore for a whole holiday's worth of clips.

2. Upload it to an online converter

Wait for the full upload to a stranger's server — with the usual privacy and size-limit problems. Family footage really shouldn't take that trip.

3. Install VLC

VLC plays AVCHD. But it's another install, blocked on many work machines, awkward on mobile, and not a shareable link.

The Better Way: Decode AVCHD Locally, In the Browser

OnlinePlayer reads the M2TS/MTS transport stream and decodes it on your own device, right in the browser — no conversion, no upload, no install.

• Hardware decoding (WebCodecs). AVCHD's H.264 video can usually be hardware-decoded by your device, so OnlinePlayer hands it to your GPU — smooth playback, low CPU, fine with HD footage.
• Software decoding (FFmpeg in WebAssembly). Where hardware decoding isn't available, it falls back to FFmpeg compiled to WebAssembly, running locally in your browser tab.

Either way, the file never leaves your computer. See hardware vs software decoding for how that path is chosen.

Step-by-Step: Play Your M2TS / MTS File Now

1. Open onlineplayer.app in any modern browser.
2. Drag your .mts or .m2ts file onto the page — or click to browse. It's decoded on your device, so it needs to be a local file; if it's in a cloud drive, download it first, then drop it in.
3. It plays — locally, with nothing uploaded.

M2TS / MTS in the Browser vs. the Alternatives

	Convert (HandBrake)	Online converter (upload)	Install VLC	OnlinePlayer
Time to first frame	Minutes	Full upload first	Install + open	Instant
Privacy	Local ✅	File on their server ❌	Local ✅	Local — nothing uploaded ✅
Keeps original quality	Re-encoded	Often re-compressed	Original ✅	Original ✅
Install needed	Yes	No	Yes	No
Works on locked-down / mobile	No	Sometimes	Limited	Yes (it's a web page)

The Honest Limits

• Dolby Digital (AC-3) surround audio is downmixed to stereo, as in any browser-based player — fine for laptops and headphones.
• AVCHD clips are often split across multiple files when a recording is long; each file plays as its own segment.
• Very high-bitrate footage that can't be hardware-decoded will lean on your CPU in software, though standard 1080p AVCHD is comfortable.

FAQ

What's the difference between .mts and .m2ts? Practically none — .mts is what the camcorder writes, .m2ts is the same stream after importing. Both play the same way here.

It's straight from my Sony/Panasonic camcorder — will it work? Yes. Consumer AVCHD is H.264 in a transport stream, which decodes cleanly — on the GPU where possible, in software otherwise.

Do I need to convert it to MP4 first? No. Open it directly — no conversion, no second copy on your disk.

Can I play it from a cloud drive without downloading? No — cloud playback only handles browser-native formats, and the AVCHD container isn't one. Download the file first, then open it locally.

Bottom Line

M2TS/MTS files are AVCHD camcorder footage wrapped in a transport-stream container the browser won't open — even though the H.264 video inside is perfectly decodable. Skip the camcorder software and the uploads: open the file in a player that decodes it locally, and your footage plays in about a second.

Play your M2TS / MTS file now at onlineplayer.app →